Method and device for performing backoff and channel access on antenna ports distributed in das in wireless lan system

Abstract

Proposed are a method and device for performing backoff and channel access on antenna ports distributed in a DAS in a wireless LAN system. Specifically, a reception STA checks whether one or more of a plurality of antenna ports are idle. When one or more of the antenna ports are idle, the reception STA performs backoff on the one or more antenna ports. When a counter of the backoff becomes 0, the reception STA performs channel access on a first channel that is commonly idle in the one or more antenna ports. The reception STA receives a PPDU from a transmission STA through the first channel.

1 . A method in a wireless local area network (WLAN) system, the method comprising:
 checking, by a receiving station (STA), whether at least one antenna port among a plurality of antenna ports is idle;   performing, by the receiving STA, backoff for the at least one antenna port based on the at least one antenna port being idle;   performing, by the receiving STA, channel access for a first channel that is commonly idle in the at least one antenna port based on a counter of the backoff becoming 0; and   receiving, by the receiving STA, a Physical Protocol Data Unit (PPDU) from a transmitting STA through the first channel,   wherein the transmitting STA operates in a system in which the plurality of antenna ports are distributed,   wherein a first primary 20 MHz channel is set for the plurality of antenna ports,   wherein the first primary 20 MHz channel is a primary 20 MHz channel that exists within one Basic Service Set (BSS), and   wherein whether the at least one antenna port is idle is determined based on whether the first primary 20 MHz channel of the at least one antenna port is idle.   
     
     
         2 . The method of  claim 1 , wherein the backoff is performed after the first primary 20 MHz channel of the at least one antenna port is confirmed to be idle continuously and after Arbitration Inter Frame Space (AIFS). 
     
     
         3 . The method of  claim 1 , wherein based on the first primary 20 MHz channel of the at least one antenna port changing to busy before the counter of the backoff becomes 0, further comprising:
 checking, by the receiving STA, whether other antenna ports except the at least one port are idle at the time when a state of the first primary 20 MHz channel of the at least one antenna port changes;   continuing, by the receiving STA, to perform the backoff based on the other antenna ports being idle; and   stopping, by the receiving STA, the backoff based on all the other antenna ports being busy,   wherein whether the other antenna ports are idle is determined based on whether the first primary 20 MHz channel of the other antenna ports is idle.   
     
     
         4 . The method of  claim 1 , wherein the first channel is a common idle channel among the first primary 20 MHz channel of the at least one antenna port and channels that are continuously idle from at least Point Coordination Function (PCF) Inter Frame Space (PIFS) before the at least one antenna port. 
     
     
         5 . The method of  claim 1 , wherein a second primary 20 MHz channel is further set for the plurality of antenna ports,
 wherein the second primary 20 MHz channel is an additional primary 20 MHz channel for each of the plurality of antenna ports.   
     
     
         6 . The method of  claim 5 , wherein based on the plurality of antenna ports including first to fourth antenna ports, the second primary 20 MHz channel includes first to fourth Distributed Antenna System (DAS) primary channels,
 wherein the first DAS primary channel is an additional primary 20 MHz channel of the first antenna port,   wherein the second DAS primary channel is an additional primary 20 MHz channel of the second antenna port,   wherein the third DAS primary channel is an additional primary 20 MHz channel of the third antenna port,   wherein the fourth DAS primary channel is an additional primary 20 MHz channel of the fourth antenna port.   
     
     
         7 . The method of  claim 1 , wherein the one BSS is a BSS of the transmitting STA,
 wherein the receiving STA does not establish pairing for each of the plurality of antennas.   
     
     
         8 . A receiving station (STA) in a wireless local area network (WLAN) system, the receiving STA comprising:
 a memory;   a transceiver; and   a processor being operatively connected to the memory and the transceiver,   wherein the processor is configured to:   check whether at least one antenna port among a plurality of antenna ports is idle;   perform backoff for the at least one antenna port based on the at least one antenna port being idle;   perform channel access for a first channel that is commonly idle in the at least one antenna port based on a counter of the backoff becoming 0; and   receive a Physical Protocol Data Unit (PPDU) from a transmitting STA through the first channel,   wherein the transmitting STA operates in a system in which the plurality of antenna ports are distributed,   wherein a first primary 20 MHz channel is set for the plurality of antenna ports,   wherein the first primary 20 MHz channel is a primary 20 MHz channel that exists within one Basic Service Set (BSS), and   wherein whether the at least one antenna port is idle is determined based on whether the first primary 20 MHz channel of the at least one antenna port is idle.   
     
     
         9 . A method in a wireless local area network (WLAN) system, the method comprising:
 checking, by a transmitting station (STA), whether at least one antenna port among a plurality of antenna ports is idle;   performing, by the transmitting STA, backoff for the at least one antenna port based on the at least one antenna port being idle;   performing, by the transmitting STA, channel access for a first channel that is commonly idle in the at least one antenna port based on a counter of the backoff becoming 0; and   transmitting, by the transmitting STA, a Physical Protocol Data Unit (PPDU) to a receiving STA through the first channel,   wherein the transmitting STA operates in a system in which the plurality of antenna ports are distributed,   wherein a first primary 20 MHz channel is set for the plurality of antenna ports,   wherein the first primary 20 MHz channel is a primary 20 MHz channel that exists within one Basic Service Set (BSS), and   wherein whether the at least one antenna port is idle is determined based on whether the first primary 20 MHz channel of the at least one antenna port is idle.   
     
     
         10 . The method of  claim 9 , wherein the backoff is performed after the first primary 20 MHz channel of the at least one antenna port is confirmed to be idle continuously and after Arbitration Inter Frame Space (AIFS). 
     
     
         11 . The method of  claim 9 , wherein based on the first primary 20 MHz channel of the at least one antenna port changing to busy before the counter of the backoff becomes 0, further comprising:
 checking, by the transmitting STA, whether other antenna ports except the at least one port are idle at the time when a state of the first primary 20 MHz channel of the at least one antenna port changes;   continuing, by the transmitting STA, to perform the backoff based on the other antenna ports being idle; and   stopping, by the transmitting STA, the backoff based on all the other antenna ports being busy,   wherein whether the other antenna ports are idle is determined based on whether the first primary 20 MHz channel of the other antenna ports is idle.   
     
     
         12 . The method of  claim 9 , wherein the first channel is a common idle channel among the first primary 20 MHz channel of the at least one antenna port and channels that are continuously idle from at least Point Coordination Function (PCF) Inter Frame Space (PIFS) before the at least one antenna port. 
     
     
         13 . The method of  claim 9 , wherein a second primary 20 MHz channel is further set for the plurality of antenna ports,
 wherein the second primary 20 MHz channel is an additional primary 20 MHz channel for each of the plurality of antenna ports.   
     
     
         14 . The method of  claim 13 , wherein based on the plurality of antenna ports including first to fourth antenna ports, the second primary 20 MHz channel includes first to fourth Distributed Antenna System (DAS) primary channels,
 wherein the first DAS primary channel is an additional primary 20 MHz channel of the first antenna port,   wherein the second DAS primary channel is an additional primary 20 MHz channel of the second antenna port,   wherein the third DAS primary channel is an additional primary 20 MHz channel of the third antenna port,   wherein the fourth DAS primary channel is an additional primary 20 MHz channel of the fourth antenna port.   
     
     
         15 . The method of  claim 9 , wherein the one BSS is a BSS of the transmitting STA,
 wherein the receiving STA does not establish pairing for each of the plurality of antennas.   
     
     
         16 .- 18 . (canceled)